Eduard Schönfeld (22 December 18281 May 1891) was a German
astronomer
An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...
.
Education
Schönfeld was born at
Hildburghausen
Hildburghausen () is a town in Thuringia in central Germany, capital of the Hildburghausen district.
Geography
It is situated in the Franconian part of Thuringia south of the Thuringian Forest, in the valley of the Werra River. The town centre ...
, in the Duchy of
Saxe-Meiningen
Saxe-Meiningen ( ; ) was one of the Saxon duchies held by the Ernestine duchies, Ernestine line of the House of Wettin, located in the southwest of the present-day Germany, German state of Thuringia.
Established in 1681, by partition of the Ern ...
, where he had a distinguished career at the
gymnasium. On leaving the gymnasium, he desired to devote himself to astronomy, but abandoned the idea in deference to his father's wishes. He went first to
Hanover
Hanover ( ; ; ) is the capital and largest city of the States of Germany, German state of Lower Saxony. Its population of 535,932 (2021) makes it the List of cities in Germany by population, 13th-largest city in Germany as well as the fourth-l ...
, and afterwards to
Kassel
Kassel (; in Germany, spelled Cassel until 1926) is a city on the Fulda River in North Hesse, northern Hesse, in Central Germany (geography), central Germany. It is the administrative seat of the Regierungsbezirk Kassel (region), Kassel and the d ...
to study
architecture
Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and construction, constructi ...
, for which he seems to have had little inclination. 1849 found him studying
chemistry
Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules a ...
under
Bunsen at
Marburg
Marburg (; ) is a college town, university town in the States of Germany, German federal state () of Hesse, capital of the Marburg-Biedenkopf Districts of Germany, district (). The town area spreads along the valley of the river Lahn and has ...
, where his love for astronomy was revived by
Gerling's lectures.
In 1851, he visited the
Bonn Observatory and studied astronomy under
Friedrich Wilhelm Argelander
Friedrich Wilhelm August Argelander (22 March 1799 – 17 February 1875) was a German astronomer. He is known for his determinations of stellar brightnesses, positions, and distances.
Life and work
Argelander was born in Memel in the Kingd ...
. In 1853, he was appointed assistant, and in the following year won a doctor's degree with his treatise ''Nova elementa Thetidis''. At Bonn he took an important part in preparing the ''Durchmusterung'' of the northern heavens. He took up the investigation of the light-changes in
variable star
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are ...
s, devoting to this work nights which, on account of
moonlight
Moonlight consists of mostly sunlight (with little earthlight) reflected from the parts of the Moon's surface where the Sun's light strikes.
History
The ancient Greek philosopher Anaxagoras was aware that "''the sun provides the moon with its ...
, were unsuitable for zone observations. The results of these researches were published in the ''Sitz. Berich. Wien. Akad.'' vol. xlii.
Mannheim Observatory
For a short time he was a ''
Privatdozent
''Privatdozent'' (for men) or ''Privatdozentin'' (for women), abbreviated PD, P.D. or Priv.-Doz., is an academic title conferred at some European universities, especially in German-speaking countries, to someone who holds certain formal qualifi ...
'' at Bonn, but in 1859 he was appointed director of the
Mannheim Observatory. The instrumental equipment of that observatory was somewhat antiquated, his largest telescope being a small
refractor
A refracting telescope (also called a refractor) is a type of optical telescope that uses a lens as its objective to form an image (also referred to a dioptric telescope). The refracting telescope design was originally used in spyglasses and ...
of 73 lines
aperture
In optics, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image o ...
, but he selected a line of work to suit the instruments at his disposal, observing
nebula
A nebula (; or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral, or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regions, such as in the Pillars of Creation in ...
e and variable stars and keeping a watch on
comet
A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...
s and new
planet
A planet is a large, Hydrostatic equilibrium, rounded Astronomical object, astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. The Solar System has eight planets b ...
s. The results of his observations of nebulae are contained in two catalogues published in the ''Astronomische Beobachtungen der Grossherzoglichen Sternwarte zu Mannheim'', 1st and 2nd parts (1862 and 1875), and those of his variable star observations appeared in the ''Jahresberichte des Mannheimer Vereins für Naturkunde'', Nos. 32 and 39 (1866 and 1875).
Bonn Observatory
On the death of Argelander, which occurred on 17 February 1875, Schönfeld was appointed to succeed him as director of the Bonn Observatory, and soon after his appointment he began his last and greatest piece of work, the extension, on Argelander's plan, of the survey of the heavens down to 23 degrees of south
declination
In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. The declination angle is measured north (positive) or ...
. The experience gained on the northern survey under Argelander's direction enabled Schönfeld to introduce some improvements in the methods employed, which increased the accuracy of this work, which was practically accomplished in March 1881, some revision only remaining to be done. These zone observations afforded 363,932 separate places of stars, and form the groundwork of the catalogue of 133,659 stars between 2 and 23 degrees south declination, which was published in 1886 as the eighth volume of the Bonn observations.
Affiliations
Schönfeld was a member of the
Astronomische Gesellschaft
__NOTOC__
The ''Astronomische Gesellschaft'' is an astronomical society established in 1863 in Heidelberg, the second oldest astronomical society after the Royal Astronomical Society.
History
In 1882, the ''Astronomische Gesellschaft'' founded t ...
from its foundation in 1863, being a member of council up to 1869, and in 1875 becoming editor of its publications and secretary in conjunction with
Winnecke. In 1878 he was elected a Foreign Associate of the
Royal Astronomical Society
The Royal Astronomical Society (RAS) is a learned society and charitable organisation, charity that encourages and promotes the study of astronomy, planetary science, solar-system science, geophysics and closely related branches of science. Its ...
.
Legacy
Minor planet
5926 Schönfeld is named in his honor.
Notes
References
*
{{DEFAULTSORT:Schonfeld, Eduard
1828 births
1891 deaths
19th-century German astronomers
Members of the Prussian Academy of Sciences
People from Saxe-Meiningen
Leibniz University Hannover alumni
University of Marburg alumni
Academic staff of the University of Bonn
People from Hildburghausen